1. Field of the Invention
This invention relates to the derivation of energy from relatively slow-moving gas streams such as wind currents, chimney drafts and the like. In particular, it is directed to an improved apparatus adapted to be driven by such a stream and to produce mechanical or electrical energy therefrom.
2. Description of the Prior Art
The most common moving gas streams are wind currents, and machines or apparatus such as windmills, intended to derive energy from such currents, have long been known and used. A principal disadvantage of all known windmills, however, resides in the fact that they are not able to derive energy efficiently from relatively-low-velocity wind currents. Thus, conventional windmills generally are considered not to be useful with wind velocities of seven miles per hour or less.